An ICO format is destined for storing icons in Windows. One such file can store a few icons with different size and colors for each. ICO supports square image 16 - 128 pixels. Today’s ICO version supports PNG and JPEG images integration, though icons are usually stored uncompressed. ICO supports true and high color depth, as well as fixed color palette 2 - 256 tones. The image structure is mostly similar to BMP, except the mast put on the background to implement the full image transparency.